The cariogenic properties of Streptococcus mutans will be analyzed utilizing genetic techniques. Strain GS-5 caries-related genes coding for sucrose metabolizing enzymes and cell surface proteins, cloned into lambda phage vectors, will be subcloned into E. coli plasmids and subsequently introduced into the streptococcal mapping vector pVA891. The resulting chimeric plasmids will be transformed into strain GS-5 with selection for erythromycin resistance. Chromosomal DNA from these transformants then will be used to map the relative position of the cloned genes by determining their frequency of cotransfer with a variety of reference markers. Since linkage analysis by transformation may not be sensitive enough to determine whether clustered genes are part of individual operons, the chromosome walking technique will be utilized for fine structure mapping.. This procedure will allow for precise localization of clustered genes identified following transformation as well as potential identification of genes adjacent to previously cloned genes.